JPH05228737A - Method for working metal of medical use - Google Patents

Abstract

PURPOSE:To precisely work a metal for medical use of titanium or titanium alloy having excellent non-elution and high corrosion resistance as the medical tools such as an implant material and a tool for the operation into the complicate shape as designed by the electric discharge machining, and fully perform the essential functions of the medical tools. CONSTITUTION:Titanium, titanium alloy, platinum or platinum alloy is used for the electrode wire to be used for the electric discharge machining. The essentially excellent non-elution and high corrosion resistance are not impaired, and blending of impurities from working jigs is avoided, leading to assurance of high corrosion resistance and non-elusion property in vivo.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The disclosed technology belongs to the field of processing technology of metal materials which are materials for medical devices such as so-called implant materials and surgical tools to be embedded in a living body for medical treatment.

[0002]

2. Description of the Related Art As is well known, the improvement of civic life is supported by the prosperity of various chemical techniques. Of these, apart from the convenience of daily life, not only the health and hygiene but also the life expectancy due to the progress of medical treatment techniques There is a significant burden on the improvement of.

Although drug administration, health management and the like make a great contribution, they are also largely responsible for remarkable progress in surgical treatment such as surgery.

It is also not to be overlooked that the remarkable development of various medical tools such as surgical tools is greatly involved.

Therefore, it goes without saying that it is extremely important to surely follow the basic design in order to fully bring out the original functions of such medical instruments such as surgical instruments. Chemical properties such as corrosion resistance and corrosion resistance, and biological properties such as non-bacterial adhesion should also be pursued.

[0006] Recently, so-called implant materials for use in a living body, such as being implanted in the human body, have been developed due to improvements in biological and anatomical techniques, and it seems that remarkable improvements in medical technology can be seen. Is becoming.

By the way, the metal materials used for such medical devices such as implant materials and surgical tools are generally referred to as medical metal materials, and when used, they are non-eluting to biochemical atmosphere and biochemical environment in the living body. In addition, there is a strict demand for invariable compatibility that maintains sufficient corrosion resistance and does not cause harmful effects over time.

[0008] Thus, metal materials that sufficiently satisfy such severe conditions have historically been subjected to various biological tests and animal experiments,
Furthermore, as a result of repeated careful clinical trials, titanium or titanium alloy (hereinafter collectively referred to as titanium metal) is considered to be the best.

By the way, in the case of a medical metal material such as an implant material, as described above, not only the design thereof is highly accurate, but also the highly accurate processing according to the design is extremely important in order to fully exert its function. Therefore, in order to deal with this, precision casting and precision machining are adopted in the manufacturing thereof.

Therefore, although titanium metal is currently used as a medical metal material, it is needless to say that precision casting or precision machining is required for processing the titanium metal material. It is a thing.

From the viewpoint of metal materials and metallurgy, titanium metal is excellent as a medical metal material in terms of non-elution property to living body and high corrosion resistance, but in terms of castability and machinability. It is also a metal with significant difficulty.

[0012] In order to cover and perform general precision casting, unfavorable casting defects such as cavities may occur, resulting in insufficient mechanical strength and poor corrosion resistance. However, there is a limit in precision machining as well.

[0013] Therefore, there is a point that the required accuracy of use as a medical device has not been satisfied, and there is a negative point that impurities are found to be found from various jigs during processing.

By the way, in the processing of various kinds of precision machine tools, jigs, etc., there are many cases in which the processing is unexpectedly complicated and the processing is difficult. In addition, the demand for high precision machining is increasing more and more, of which electrical discharge machining technology is widely used as high precision machining technology in various machine manufacturing industries, and further research and development is being carried out. There are two types of processing machines as general modes, one of which is a small-diameter electrode wire, and the electrode wire is moved in the longitudinal direction while a predetermined tension is applied to the electrode wire. A machine called a wire electric discharge machine, which is an apparatus for generating an electric discharge between a workpiece and an electrode wire through a working fluid such as water, and processing the workpiece in a predetermined manner by the discharge energy. And two Basically there is a machine which is referred to as the seed machine and carving form a similar processing principle discharge machine.

The electrode wire used in such an electric discharge machine is generally made of copper or a copper alloy in terms of conductivity, strength and durability.

Thus, the electric discharge machine, which has a merit that it can be machined as designed with high precision and close to it, has the property that part of the electrode wire material used adheres to the work piece. That has been confirmed so far by experiments.

The fact is that not only when the material of the electrode wire to be processed is copper or a copper alloy, but also titanium metal which has been adopted as a medical metal material which has recently been heavily used is a workpiece. Also in the case, the fact that the work piece adheres to the titanium metal surface is also known by experiments,
Therefore, titanium metal, which has good compatibility with living organisms and has excellent properties as a medical metal material, cannot obtain the high-precision processing precision required by design even by precision machining, and as a result, as a medical metal material. There was a drawback that the original function of could not be fully exerted.

Further, even with the electric discharge machining technique, which is capable of highly accurately machining a highly difficult work piece having a complicated shape, it cannot be machined as a medical metal material, and it follows the design. However, there was a neck that prevented the emergence of medical devices such as implant materials and surgical tools.

[0019]

The object of the invention of the present application is to solve the problems in the workability due to electric discharge machining when titanium metal based on the above-mentioned prior art is used as a medical metal material. For the medical metal materials of the above, theoretical analysis of the peripheral technology of electric discharge machining technology accumulated so far and accumulation of experimental data, and by these analysis studies, to the highly accurate and highly corrosion resistant medical metal material Based on the repetition of the application experiment of the processing technology, it produces non-elution property to living body and high corrosion resistance, and it can be processed freely as a medical metal material of titanium metal. It is intended to provide an excellent method of processing a medical medical metal material.

[0020]

BACKGROUND OF THE INVENTION As a result of various theoretical and experimental analyzes of electric discharge machining technology in alloy machining and its peripheral technologies, the inventor has found that titanium or titanium alloy is used as an electrode wire for electric discharge machining. Alternatively, platinum or
Titanium as a medical metal material or a titanium alloy is non-eluting in vivo and maintains high corrosion resistance by using a platinum alloy to which a platinum group element is added in a predetermined manner, and further, sufficient discharge By gaining the knowledge of high-precision processing technology, it will broaden the path to practical use.

[0021]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the structure of the invention of the present application, which is based on the above-mentioned object and has the scope of the above-mentioned claims, is intended to solve the above-mentioned problems. When titanium or titanium alloy is used as the medical metal material used for the medical device of, when performing precision machining according to the design by electrical discharge machining, titanium metal, or platinum, or platinum in which a platinum group element is added to the electrode wire By performing the electric discharge machining in the same manner as in the general embodiment using a metal, it is possible to fully exhibit the original excellent characteristics of the medical metal material, and similarly, there is no contamination of impurities from the machining jig. It is a technical measure that can provide a predetermined excellent medical device without any action.

[0022]

Embodiments of the invention of this application will be described below with reference to the drawings together with known examples.

Table 1 shows experimental examples together with known examples.

[0024]

[Table 1] The electric discharge machine to be used may be a normal wire electric discharge machine, but the material of the electrode wire used in the invention of this application is JI.
S1 type, JIS2 type, or JIS3 type titanium may be used, but a titanium alloy such as JIS12 type may be used.

Also, like titanium, it is non-eluting in the living body even when it is embedded in the living body, and has excellent corrosion resistance and effective compatibility that does not have a harmful effect on the living body. Platinum, which is one of the few metals that has been confirmed in the test, or a platinum alloy (abbreviated as platinum metal) to which a predetermined amount of platinum group element has been added, is used as a medical metal material such as titanium or titanium alloy ( It has been confirmed in advance by experiments that the excellent non-elution property and high corrosion resistance of titanium metal) are not impaired.

The electrode wire described above is manufactured by a known melting and processing means.

As a specific example, a titanium rod compatible with JIS 2 type titanium or JIS 12 type titanium alloy is heat-treated and wire-drawn. On the other hand, with respect to platinum metal, arc melting is also a well-known melting technique. After the platinum metal was melted, heat treatment and wire drawing were performed to produce wire rods each having a predetermined shape and a diameter of 0.2 mm and a length of 3000 m.

In this case, platinum, iridium, rhodium, and platinum group elements added and blended as platinum metal are used.
Ruthenium is the mechanical property of the wire as electrode wire,
It has been confirmed by experiments that it is ideal in terms of corrosion resistance and, ideally, the addition amount is 30% or less from the viewpoint of workability.

Regarding titanium metal, JIS 2 type metal materials and JIS 12 type titanium alloys, which are the best at present by biological tests, animal experiments, and clinical tests, were used.

The wire electric discharge machining conditions have a pulse width of 0.15 to 1.85 for each condition change range.
μs, pulse dwell time 2 to 16 μs, current peak value 4.5 to 58 A, no-load voltage 30 to 100 V, electrode wire feed speed 6 to 15 m / min, electrode wire tension 0.1 to 2 0.0kgf, processing speed 0.1-2m
As a result of m / min, it was confirmed that specific processing conditions made it possible to process a non-processed medical metal material with high precision as designed.

Next, the examples of the experimental examples in Table 1 will be described in detail. In the experimental example of Example No. 1, pure titanium JIS2 type is used as the medical metal material, and pure titanium JIS2 is used as the electrode wire. The pulse width is 0.2 μs, the pulse dwell time is 12.0 μs, the current peak value is 29.0 A, the no-load voltage is 100 V, the electrode wire feed speed is 7.0 m / min,
The tension of the electrode wire is 1.0kgf and the processing speed is 0.5
It is the data obtained by experimenting with mm / min. Next, in the experimental example of Example No. 4, a JIS12 type titanium alloy material was used as the medical metal material, copper was used for the first processing as the electrode wire, and pure titanium JIS2 type material was used for the second processing. The second machining is a mode in which the surface at the time of the first machining is electric discharge machined at 100 μm, and the electric discharge machining conditions are as follows: the first time has a pulse width of 0.5 μs and a pulse pause. Time is 16.0 μs, current peak value is 18.0 A, no-load voltage is 70 V, electrode wire feed speed is 7.0 m / min, and electrode wire tension is 1.
0kgf, processing speed 2.0mm / min,
The second electrical discharge machining conditions were pulse width 0.2 μs, pulse pause time 12.0 μs, current peak value 29.0 A, no-load voltage 90.0 V, electrode wire feed speed 7.0 m.
/ Min, the tension of the electrode wire is 1.0 kgf, and the processing speed is 1.5 mm / min.

The experimental example of Example No. 4 was obtained from the data obtained by the inventor who conducted the examination and experiment from all angles, and the electric discharge machining speed for titanium metal, which is a medical metal material, was increased to make it more economical. This indicates that it is a processing condition.

Then, the titanium metal sample as a medical metal material produced as described above was immersed in 35% hydrochloric acid at 80 ° C., which is a corrosion resistance test in a harsh environment after alcohol cleaning, and was subjected to a change with time. The result of measuring the elution amount of titanium is shown in FIG.

As shown in FIG. 1, the amount of titanium eluted from the medical metal material processed according to the invention of this application is significantly smaller than that of a conventional electrode wire using a conventional copper electrode wire. It can be seen that it is an excellent medical metal material even when compared with the titanium material.

[0035]

As described above, according to the invention of this application, the basically processed metallic medical material made of titanium metal has a high precision and can sufficiently exhibit its original function as the medical metallic material. Not only the processing accuracy can be easily obtained, but also the impurities from the processing jig are not mixed in, and the excellent corrosion resistance of titanium metal is not impaired at all. Therefore, it is possible to produce an excellent medical metal material that has sufficient properties and does not give any harmful effect.

Further, it is possible to make full use of the characteristics of precision machinability due to electric discharge machining for implant materials and medical instruments such as surgical instruments which require high precision machining, and it is difficult to process due to complicated shape and material Despite the difficulty of machining, precision machining as designed can be done, and it can make a great contribution to the medical and dentistry and other therapeutic academia, and also contribute to the electrical discharge machining industry in various machine manufacturing industries as much as possible. The excellent effect that the degree is high is exhibited.

Therefore, as a result, there is an effect that the average life expectancy of human beings can be improved, the quality of health and sanitation can be improved, and the contribution to the livestock industry can be gradually increased.
It has the advantage that even the industrial world can fully overestimate it.

[Brief description of drawings]

FIG. 1 is a graph showing the results of both elution measurement data of titanium based on an example of the invention of this application and an experimental example of a known example.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuaki Koyama 2-12-30 Aoyagi, Soka-shi, Saitama Ishifukukin Metal Industry Co., Ltd.

Claims (3)

[Claims] 1. A method of machining a titanium metal material of a medical metal product made of titanium metal by electric discharge machining, wherein the electrode wire used for the electric discharge machining is used as titanium metal or platinum metal. Processing method of medical metal material. 2. The method for processing a medical metal material according to claim 1, wherein the titanium metal is titanium or a titanium alloy. 3. The method for processing a medical metal material according to claim 1, wherein the platinum metal is platinum or a platinum group-added platinum alloy.